The invention is related to a housing for data storage devices or for accommodating such data storage devices.
To operate for example a personal computer, usually a computer system is required comprising a disc drive, a central processing unit, a floppy disc drive as well as other devices which are assembled within a cuboid shaped housing. Fans are usually installed in such housings, maintaining an air-flow through the housing to facilitate the cooling of electronic and mechanic components while the computer is operating.
The acoustic noise emitted by such computers is often perceived as unpleasant by computer users. Regarding the acoustic noises solely generated by the fans, these are located in a middle-frequency range and therefore act subjectively less disturbing as the high-frequency acoustics, which are radiated by the computer and the alternating mix-mode noises generated by the mixture of noises. The high-frequency sound involving frequencies that may extend up to 9 kHz or more, are mainly generated by the drive motor of the data storage device. The disc media is driven at high velocity by the drive motor. Even if the high-frequency noise radiated by the housing and through the air vents only has a relative low amplitude, it annoys due to its permanent presence and particularly in a room (i.e. large area office) where a number of such computers are in use with the according noise emission. In such rooms a permanent whistle and warble is audible, which impairs the health and labor capacity of those who are working in such environment.
Due to severe competition, PC""s and workstations have strongly diminished in price value and are meanwhile considered as mass products. A warranty period of 36 months, is meanwhile at least granted by all large vendors world wide and treated as a usual practice. Due to the fast technological progress the purchase value of a computer declines within shortest time, long before the warranty period expires. This leads to the circumstance that manufacturers and suppliers proceed to carry the risk of RMA handling, despite the fact that the commodity has lost its value to a great extent. RMA cases are mainly caused by those computer components which contain moving mechanical or force-driven parts. The failure of the mass-storage-device, the disc drive, usually causes the greatest single damage for the user as well as the manufacturer or supplier. Modem disc drives are sensitive against shock and in some instances, due to elevated power consumption, also against overheating. Already slight shocks may lead to a head crash. Such shock influence caused by the user, onto a commonly constructed computer, are not provable for the manufacturer or supplier. Therefore such defects automatically lead to a warranty obligation.
The state-of-the-art technology provides a variety of single or even combined solutions for the noise-reduction of computer housings, the cooling of oscillating devices and shock absorption for sensitive devices. The following publications on the state-of-the-art are considered as known.
DE-GM 297 04 870, DE-OS 38 23 656, DE-GM 296 02 346, DE-OS 43 14 199 U.S. Pat. No. 5,192,143, U.S. Pat. No. 5,510,954, U.S. Pat. No. 5,596,483, U.S. Pat. No. 5,287,244 U.S. Pat. No. 5,214,459, U.S. Pat. No. 5,668,697, U.S. Pat. No. 5,654,875, U.S. Pat. No. 4,812,932, U.S. Pat. No. 5,235,482, U.S. Pat. No. 5,469,311, U.S. Pat. No. 5,638,895, U.S. Pat. No. 5,801,899
In the DE-GM 297 04 870 an extensive de-coupling of body-oscillation is achieved by suspending the disc drive in o-rings made of rubber-elastic materials and lining the inner sides of the computer housing with rubber-cork mats. The disadvantage here is, that depending on the type of disc drive model, cumbersome adjustments of the suspensions are to be taken care of. In addition it is uncertain whether a slipping of the device during transport is prevented under all circumstances. This type of suspension contradicts the emphasized manufacturer specifications regarding the firm assembly of a disc drive. A disc drive suspended within a 5xc2xc inch slot-frame is positioned in the immediate rear of the computer front lid of standard computer housings. Thereupon one has to permanently shut a front lid to fully reduce the noise. A disc drive suspended within a 5xc2xc inch slot-frame can only be cooled exclusively by a fan from the bottom or with tiny fans from the side. An air stream only blowing at the bottom is often not sufficient. For the purpose of secure cooling, disc drive manufacturers usually prescribe that an air stream has to be maintained above the top side as well as the bottom side. As no further passive cooling is provided for the disc drive, a failure of the fan will lead to overheating in most instances. This is particularly fatal when a computer is operating unattended and no immediate response is given to a system warning indicating fan failure. Even if a fan failure recognition invokes an automatic system shut-down, this is equivalent to a system failure which has to be repaired prior further operation. Eventually the application of cork-rubber mats does not meet the UL regulations regarding fire hazards in electric devices.
The DE-OS 43 14 199 describes an artifice for conductive cooling of oscillation attenuated devices which are mounted within a closed housing. It is uncertain if the here described method of cooling is sufficient enough to cool, disc drives dissipating up to 20 W, exclusively by thermal conductive heat-relief, with an appropriate magnitude. Computers are specified with an ambient operating temperature of 35xc2x0 C. for the medium latitudes and 40xc2x0 C. for the warmer regions. However, disc drives available in the mass market are only offered with a maximum specified surface temperature of 55-60xc2x0 C. The specified thresh hold temperature for maximum life time is most often located 10-15xc2x0 C. below the maximum rated temperatures. This signifies that for a long life time a very effective cooling has to be implemented. For reasons of extensive assembly requirements the here described method is unusable for the mass market in any instance. Furthermore disc drives may not be mechanically altered due to warranty considerations. An effective heat-relief by means of copper braiding, is only achieved by soldering or welding onto the disc drive.
In the U.S. Pat. No. 5,192,143 shock absorbers for disc drives are described. It is not evident if these shock absorbers also enhance an effective noise reduction. Furthermore it is doubtful that these shock absorbers are sufficient to safe guard a disc drive against a shock of 30 g applied onto the housing during continuos operation. A shock of 30 g is already reached when a computer gets hit by a vacuum cleaner. Regular 3xc2xd inch disc drives are specified with a maximum shock stress of 10 g during operation. No concerns about cooling the disc drive are to be extracted from this publication.
The so far as best known state-of-the-art is described in the U.S. Pat. Nos. 5,510,945 and 5,596,483. However, the disadvantage here is the hermetically encapsulated disc drive. Thereupon an active or passive direct air cooling is not possible. Here, the cooling of the disc drive is exclusively only achieved by thermal conductive heat-relief. The necessary air vents on the deck of the computer does not conform with any housing standards. The guided air stream depends too much on the implemented components and is already warmed up prior to reaching the location of the described heat-sink. No redundant cooling is existing. Two or even more only very slowly rotating fans and a convection air-stream guided through the power supply, are in total only sufficient for a computer equipped with low-power components. The encapsulation of the disc drive restricts the cooling to such an extent, that this method is not applicable in conjunction with powerful disc drives (refer to c""t magazine edition 19/1998, start page 136 on page 142). The here described cooling pouch filled with liquid is pressed onto the bottom and top side of the disc drive with a broad two-dimensional shaped metal bracket in order to achieve a good thermal contact. The bottom side of a disc drive, regardless of what model type, is usually equipped with a printed circuit board on which sharp edged SMD components and connector pins are mounted. It can not be excluded that the efficiency of this cooling method may be endangered by the tearing of the cooling pouch during assembly, transport or while in operation. In addition the assembly and disassembly of the disc drive appears cumbersome here.
No concept is recognizable by the enlightenment extracted from the present state-of-the-art, that simultaneously contents the following criteria: 1) sufficient noise reduction in respect to subjective perception, 2) sufficient cooling for long life time even for powerful data storage devices within the narrow temperature range of data storage devices, 3) for the shock sensitivity of data storage devices a sufficient safe guard against shocks, which are possible in a typical working environment, 4) a solution for the previously described necessities with the least possible investment of material and assembly costs. Particularly no universal concept is recognizable within the present state-of-the-art that enables step wise modular extendable measures regarding noise reduction as well as cooling for the multitude of available data storage devices on the market, which individually develop different types of noise emission and heat dissipation.
The disc drive will be considered as the main cause of generating the subjectively unpleasant noise development. With the present state-of-the-art disc drive technology, this circumstance is well founded therein, that a disc drive contains at least four distinct noise sources. The bearings of the drive motor and the disc media are responsible for the high-frequencies on one hand and the alternating magnetic fields generated in the drive motor on the other hand. The low and also high energetic oscillations are caused by the unbalance, due to manufacturing tolerance, of the disc media on the one hand and by the acceleration and deceleration forces of the read/write heads on the other hand. Due to the world wide regulated limits of RF radiation by electric devices, the application of metal housings for computers remains indispensable for an effective EMI protection. The usual metal-to-metal-assembly of disc drives in housings, inevitably leads to an amplified radiation of sound noises by the metal surfaces. Moreover, depending on the type of housing construction, particularly the high-energetic low-frequency oscillations cause an uncontrolled stimulation of the sheet metal at different harmonics of the basic frequencies.
Therefore this invention is based upon the objective, to seize measures within the previously explained type of housing, which will suppress the subjectively unpleasant noise radiation as extensively as possible. Simultaneously the data storage device is to be safe guarded against typical shocks that may reach the housing. Further, noiseless and failsafe cooling measures are to prevent the thermal self destruction of the data storage device. Furthermore, the determined measures are to be organized within a unified concept, as to enable step wise modular extensions, so that only the necessary and sufficient measures are to be implemented for the different power classes. In addition the design of the housing should enable cost efficiency in mass production, regarding the assembly steps as well as the invested material. In conjunction with the mentioned modular concept, an optimized cost reduction is to be achieved by a production turn out with a variety of different computer models.
The solution of the assigned task as set forth below and the majority of the particular embodiments displayed here, were designed in their construction and therewith geometrically for the system integration of data storage devices into a computer/server or other housing. However, as the preferred embodiments eventually reveal, it becomes self evident that at least some portions of the invention may very well become integrated parts of the data storage device itself. To avoid any terminology confusion, per definition the term disc drive or data storage device is applied when referring to a typical data storage device as shipped by drive manufacturers. Per definition the term xe2x80x9cdrive assemblyxe2x80x9d as used here, is the part of a data storage device onto which a drive motor is assembled which drives the data storage media. A drive assembly may comprise further components such as read/write head actuators and other elements. A data storage device could per example also be a CD-ROM drive, a floppy drive, a magneto optical drive and so forth.
The basic principle which is applied in accordance to the invention, is based upon de-coupling and oscillation-attenuation of the body- and air-sound, of all motor driven data storage devices installed in the housing relevant for the development of noise, against the common chassis. A combined thermal conductive and active and/or passive air-cooling is applied to achieve noiseless cooling of the storage device. Passive cooling, which makes the forced-cooling of motor driven data storage devices by fans dispensable, will lead to a further reduction of noise emission. If a motor driven data storage device is arranged in an air-vented hollow shaft in such a manner, that the internal perpendicular dimension of the shaft is scaled in relation to the wavelength of the expected noise pressure, the noise pressure will already be attenuated while unfolding in the adjacent air media. This will lead to a further reduction of the noise emission.
In accordance to the invention, the assigned task is solved by any given single or suitable combination of the independent claims 1, 17, 33, 49, 64 and 70.
The drive assembly of a disc drive is for example arranged in an assembly unit, which has a stiff damper-carrier-surface facing to the front of the assembly unit. The assembly unit with rectangle edges facing to the front is for example attached to the damper-carrier-surface with rivets and forms a singular mechanical unit with the assembly unit. As will be described in the following embodiments, this unit is preferably mounted onto the front panel of the chassis. However, any other suitable supporting-surface within the housing is bearable in mind. The front panel is preferably constructed as stiff as possible or may be reinforced with stiff surface means within the mounting area. The fastening means such as screws or other, gripping into the damper-carrier-surface, are supported on a stiff damper-fastening-surface facing to the outside of the front panel. A carrier-surface-oscillation-damper consisting of semi-elastic material, is located between the damper-carrier-surface of the assembly unit and the inner side of the supporting-surface. A fastening-surface-oscillation-damper consisting per example of the same material, is located between the assembly-damper-surface and the outside of the front panel. This semi-elastic material is fabricated in such a manner, that it is by far more elastic than the front panel but at the same time indicating enough support-force for the assembly unit including the supported disc drive. Furthermore, the fastening edges of the assembly unit serve the purpose of an end position for the fastening means that grip into the damper-carrier-surface. Therewith, adjusting the fasting means is dispensable. Simultaneously the total layer structure, consisting of the damper-carrier-surface, reinforced front panel, damper-fastening-surface and the two oscillation-dampers is matched with the fastening means in such manner that the two oscillation-dampers sustain under slight pressure, when the fastening means gripping into the damper-carrier-surface have reached the end position. Due to the sustained pressure of the dampers, the fastening means are to be considered as conditionally firmly attached to the damper-fastening-surface. Within the limits of the here occurring oscillation forces the damper-fastening-surface and the damper-carrier-surface remain in a continuous, relative rigid connection. The stiff structure of the two as two-dimensional evolving constructions, causes the oscillations generated by the disc drive to mainly introduce perpendicular into the dampers. Furthermore, the fastening means are always isolated in particular against the carrier- or supporting-surface between the two dampers and kept movable perpendicular to the damper surface or held at distance.
The herein above described reinforcement of the front panel, with reinforcement panel located in the mounting area of the assembly unit, may alternatively be achieved particularly in mass-production, by embossing support beams into the sheet metal of the front panel, so as to obtain the necessary stiffness of the supporting-surface or any other suitable surface within the housing. The herein above described damper-carrier-and-fastening-surfaces may alternatively adapt any other geometric structure, which will indirectly fulfill the task of achieving a two-dimensional-like contact with the damper surfaces. The surface contact is not compulsory of plane-parallel structure. Also, the dampers are not obliged to indicate plane-parallel structures or regular surfaces.
If the previously described damper layers are embodied symmetrically, this is considered as a low-pass with frequency independent coupling at the front panel between the two dampers. Coupling is conditioned due to the fact that two 180xc2x0 phase-shifted oscillations which are equal in amplitude and frequency, hit the front panel with anti-parallel vector-direction. Coupling plays a subordinate role with frequencies ranging in the middle or even upper range, because the damping factor of this low-pass system is high. Due to the large two-dimensional embodiment of the dampers, the application of a soft damper material with enough support-force is possible. The stiff embodiment of the damper- carrier- and fastening-surfaces enable a strong distribution of the vertical oscillation forces throughout the surface of the dampers. A damper system in this configuration has a sufficient damping factor in the low-frequency range even under the condition of coupling. The low and high-energetic unsteady oscillations of a disc drive are caused by the read/write heads. Each data storage device model has its own characteristic head-oscillation behavior. The low-frequency and high-energetic steady oscillations are caused by the unbalance of the rotating disc media. Every data storage model has a typical rotational frequency according to its rotating speed. As the rotational frequency inclines linear with the rotating speed, the oscillation energy inclines quadratic with inclining rotating speed. The herein above described damper system is capable of attenuating the steady oscillations very effectively, if the layer-width of the carrier-surface-oscillation-damper and the layer-width of the fastening-surface-oscillation-damper are matched in their relation in such manner, that the attenuated oscillations of both dampers, with the typical rotational oscillation-frequency of the rotating media, hit the supporting-surface in-phase with anti-parallel vector-direction. Under these conditions counter-coupling takes place at the supporting-surface of the damper system. In accordance to the invention this frequency-dependent counter-coupling condition, induces a nearly complete self-elimination (the necessary difference in damper width causes a difference in amplitude) of the oscillations in the area of the supporting-surface. This signifies that two oscillations equal in phase and hitting the supporting-surface in opposing directions, nearly totally avoid any movement of the supporting-surface. A further precondition for the counter-coupling condition is the choice of a damper material with a particularly low speed of propagation for oscillations (considerably lower than i.e. air), in order to take an influence on the phase within the range of a half-wave (xcex/2) with the here possible dimensions of dampers. Due to the virtually rigid connection between damper-carrier-surface and damper-fastening-surface, it is secured that the necessary phase conditions are permanently maintained (phase-locked-loop). Thereby, the oscillation energy is effectively attenuated against the reinforced supporting-surface and in conclusion also against the chassis. Simultaneously the self-oscillation of the data storage device is reduced to a negligible minimum, despite the fact that the data storage device is mounted soft relative to the housing. In that case, assembly prescriptions for data storage devices are fulfilled. A data storage device is to be assembled in such a manner that self-oscillation is avoided in order to prevent position-corrections of the read/write heads, which would resemble a loss of performance.
In a further embodiment of the invention, the herein above described damper system is equipped with a gadget for fast and easy tuning of the counter-coupling, to meet the counter-coupling condition. A tuning-plate is inserted between the damper-fastening-surface and the fastening-surface-oscillation-damper. The tuning-plate is guided by the fastening means. A thread-extension with a screw-thread is for example located on the middle outside face of the damper-fastening-surface. It is now possible to regulate the distance between the tuning-plate and the damper-fastening-surface with an appropriate screw. Therewith, the tension pressure between the two dampers may be elevated and simultaneously the layer width may be varied in a limited scale. As long as the dampers have been roughly dimensioned with the right proportion, this gadget enables a fine tuning to optimize the phase conditions. It may be of advantage if the two dampers are configured with different types of materials in order to further fine-tune the damper characteristics or that the dampers are each configured in layers consisting of materials indicating different properties. In order to be frequency independent in the vertical direction of a push-pull attenuation, a further construction may be useful, which connects the damper-carrier-surface and the damper-fastening-surface in a cross-over manner or force diverting, so that both panels always conduct opposing movements in the first place. Under such circumstances counter-coupling would be given at all frequencies with a symmetric embodiment of the dampers. However, the here necessary construction will be comparably lavish in relation to the gain of performance.
Within the framework of this invention it has become evident that the previously described symmetric push-pull damper version is sufficient for the present state-of-the-art data storage devices and in addition also very cost efficient in production.
Within the framework of a further embodiment of this invention, the carrier-surface-oscillation-damper and the fastening-surface-oscillation-damper may be blank-spaced with holes or passages in accordance to the individual support-force distribution. This measure induces a differentiated mass-distribution of the damper mass in such manner that even without adjustable fastening means, the data storage device unit will maintain a rectangular position relative to the front panel after assembly. The elasticity of the dampers and therewith the support-force has to be chosen in accordance to the different possible loads of this invention in order to make different types of compensations dispensable. Therewith, only one type of damper shape is necessary for the different assembly variations in mass production.
Due to the described embodiments of the invention and by appropriate dimensioning of the damper layer-width, the data storage device is also effectively safe guarded against shocks applied to the housing. With the previously described type of suspension a crank-bearing or xe2x80x9cpivotxe2x80x9d for the assembly unit is formed at the front panel between the two push-pull dampers, in vertical as well as horizontal direction. Conditioned by the embodiment of the damper surfaces and the position of the suspension points of the fastening means gripping into the damper-carrier-surface, the shock absorbing effect is controlled in such manner, that in perpendicular direction to the disc media more freedom of movement is permitted as in horizontal direction. Therewith, a stronger shock absorption is enabled in perpendicular direction to the disc media, as in horizontal direction. The shock sensitivity is always greatest perpendicular to the media, because the read/write heads move extremely close above and along the media.
The cost efficient damper system, in accordance to the invention, simultaneously serves the purpose of reducing noise as well as particularly an effective shock absorption and as a safe guard for the data storage device against shocks.
The assembly unit allocated to the drive assembly, may indicate different properties depending on the requirements and may serve the purpose for the assembly of further components beside the disc drive, as set forth below. Depending on the type of data storage device and the type and extent of additional components assembled in or onto the assembly-unit and depending on the composition of the assembly-unit material, the high-frequent oscillations emitted by the data storage device may lead to an amplification of the high-frequent noises due to resonance with the assembly unit or other components or their combination. In such instances, by a further embodiment of the invention in accordance to the invention, an oscillation-attenuating-layer is aligned between the assembly unit and the drive assembly, which has a high attenuation for high-frequent oscillations. Thereby, the fastening means gripping into the drive assembly are supported by oscillation de-coupling mounts on the assembly unit allocated to the drive assembly. Thereupon, a high-frequent oscillation generated by the data storage device is attenuated against the assembly unit, with further attached components in such a manner, that during operation of the computer the usual high whistle tone is not or hardly no longer perceivable.
Also here it may be of advantage if the drive assembly, the oscillation-attenuating-layer and the assembly unit are attached with a sufficient two-dimensional contact-surface in order to distribute the oscillation energy well across the surfaces, so that a maximum exploitation of the attenuation effect is achieved. Particularly hard-rubber washers which are for example attached to metal washers, are to be considered as mounts. For a better distribution of the torque-force on the side-wall-surface-means of the assembly unit by the fastening means gripping into the drive assembly, it has revealed to be advantageous in the framework of this invention to unify the mounts into one two-dimensional shaped component. The singular hard-rubber washers now form a rectangular long rubber part for each side of the drive assembly with a plurality, in this special instance three through-hole openings and an appropriately equally shaped metal piece also with three through-hole openings. This construction will be referred to as a torque-momentum-distributor-bridge further on. The torque-momentum-distributor-bridge is constructed in such manner that the individual torque momentum of the fastening means are equally distributed across the assembly-unit-side-wall-surface-means by the hard-rubber-layer. In the framework of this invention a 4 mm thick sheet metal has proven to be useful. The same effect may be achieved in other embodiments with thinner sheet metal shaped as U-profiles. Thereupon, the device is nearly fully isolated against the assembly unit in respect to high-frequent body oscillations. As such, the remaining relevant effective radiation surface for high-frequent oscillations are limited to the surface of the disc drive on one hand and an additional oscillation attenuation is achieved on the other hand. The fact that the oscillating surfaces adjacent to the surrounding air media have been reduced to the minimum of the data storage device surfaces, is now of particular advantage.
With the measures described herein above and the arrangement of the structure apparent in the drawings, a hollow shaft is formed around the data storage device with the aid of the damper-carrier-surface, the assembly unit itself or by the assembly unit and the above located cage, so that the high-frequent sound radiated into the ambient air is reflected away from the front panel into the direction of the housing rear. The inner sides of the housing lid and the bottom surface of the chassis may at least be partially lined with a flame thwarting sandwich material facilitating a further reduction of noise development. However, the application of foam linings will be dispensable as the further course of this description will reveal.
If one or more data storage device(s) is/are assembled in a housing of the previously mentioned type by insertion of an oscillating-damping-layer, it is recommended that the oscillation-damping-layer additionally indicates good thermal conductive features, that the layer indicates sufficient surface contact respectively to the side-wall-surface-means of the assembly unit, and that the assembly unit(s) is/are fabricated with a good thermal conductive material.
The largest heat sources of the data storage device are represented by the drive motor for the disc media and the actuator of the read/write heads. Usually these are firmly attached to an aluminum cast part which forms the drive assembly. Therefore, the best possible thermal interface is determined by the surface means on the perimeter of the drive assembly, which also serve the purpose of mounting. However, as the surface means of the drive assembly usually indicate surface-irregularities, it is required to structure the attachment in such a manner, that the side-wall-surface-means press the thermal conductive oscillation-attenuating-layer onto the surface means of the drive assembly with sufficient pressure, in order to achieve a good surface contact with the drive assembly. These circumstances are assisted by the fact that the same measure is required in the herein above described high-frequent oscillation attenuation. Thereupon, the combination of both constructive measures do not contradict. It has revealed in the framework of this invention, that an oscillation-attenuating-layer with good thermal conductive features and a width of about 0.45 mm is enough to sufficiently attenuate, equalize the surface irregularities with appropriate attachment pressure and achieve a highly efficient thermal conduction onto the assembly unit. Within the framework of this invention the application of an aluminum material is preferred for the assembly unit. The aluminum assembly with its good thermal path to the drive assembly, creates a significant enlargement of the data storage device""s cooling surface. As such, an assembly unit fabricated with aluminum serves the additional purpose of a heat-sink besides supporting a disc drive. As long as the assembly unit is at least partially arranged within the air circulation of the housing, this passive cooling method is sufficient for most of the disc drive models in the middle performance range.
In the framework of this invention it is useful to apply a silicone-gummed ribbon shaped isolation material as oscillation-attenuating-layer. However it is also bearable in mind that the silicone material is laminated directly onto the assembly unit. Further a lamination of the drive assembly surface-means on the perimeter of the drive assembly may also be considered. The variety of layer geometry as set forth below, will further on be referred to as oscillation-attenuating-layer.
Within the framework of a further embodiment of the invention, the cooling-force may now be elevated step wise depending on the requirements. According to the preferred embodiment of the invention, the cooling-force is elevated by supplementing the assembly unit, which is allocated to the drive assembly, with cooling-fins or heat-sinks. It is useful that these cooling elements at least partially project into the air stream generated by the main fan(s) of the housing. In the framework of this invention the cooling fins are preferably arranged on the outer sides of the assembly unit. Thereby, the heat conducted away by the side-wall-surface-means of the assembly unit, is conducted with the shortest possible path into the cooling elements. Assembly units fabricated with copper or other good thermal conductive materials are also bearable in mind. It proved to be advantageous within the framework of this invention to either attach the assembly unit in direct metallic surface contact with distinct embodied heat-sinks by screw bolts or to apply assembly units with integrated cooling fins. If the heat sink and the assembly unit are individual components, it is advantageous in terms of assembly to structure the assembly unit as a singular component. If the cooling fins are integrated into the assembly unit it is advantageous to structure the assembly unit as two components. Aluminum profiles are to be considered as optimum. Within the framework of the various different examples as set forth below, it will become apparent that the assembly unit allocated to the drive assembly may also exclusively only serve the purpose of supporting the cooling elements. Thereby, the assembly unit does not always compulsively serve the purpose of simultaneously supporting a data storage device.
In the framework of a further embodiment of the invention, an additional elevation of the cooling force may be achieved by, alternatively or additionally to the previously mentioned heat-sinks, applying a fan which is mounted onto a side-wall-surface-means of the assembly unit. For this purpose, a group of holes are arranged on the side-wall-surface-means above and below the disc drive, which in total forms a passage for the air stream generated by the fan. As to guide the complete air stream generated by the fan through the passage, a gasket is arranged as support between the side-wall-surface-means and the fan. Thereby, the vendor prescriptions of maintaining an air stream above and below the disc is fulfilled.
The fastening means for the fan, gripping into the side-wall-surface-means of the assembly unit are supported directly on the fan and guided through holes in the gasket. It is useful to arrange threads or self cutting threads in the side-wall-surface-means of the assembly unit for this purpose. If the fastening means of the drive assembly are supported on torque-momentum-distributor-bridges, the gasket has to indicate at least one passage on one side for the bridge. Thereby, a sufficient air stream is achieved above and below the data storage device. In the maximum extended construction of the cooling method as described herein above, the invention permits a failure of the data storage device fan at an ambient operating temperature of 40xc2x0 C. without that even the present most powerful 1 inch height disc drives will exceed their maximum rated thresh hold temperatures. However, the fact that it is possible to maintain the most powerful disc drives with intact cooling system, even at the vendor specified thresh hold temperatures for maximum life time, up to the most extreme ambient temperatures, seems to be far more important. As such hereby, a decisive contribution to the life time of the disc drive is achieved. This cooling method is not limited to 1 inch height disc drives. With adapted geometric embodiments, this method is also applicable to 1.6 inch (and greater) height disc drives available on the market and of course any other type of motor driven data storage device.
In a further embodiment of the invention, it is advantageous in respect to environmental considerations, to renounce the application of sandwich foam-linings arranged on the inner sides of the housing. In order to maintain the so far achieved noise emission specs, it evolves as necessary to reduce the number of noise sources within the housing and seize further measures. As already described in the introduction, the fans and in particular a plurality of fans in the computer, also cause noise. According to the state-of-the-art the CPU is cooled passively with a heat-sink. Thereby, a CPU fan is omitted. Furthermore the additional fan located in the air-inlet of the housing is omitted. Due to an advantageous embodiment of the passive disc drive cooling method the disc drive fan will eventually be dispensable.
In a further embodiment of the invention, the heat-sink is integrated with the assembly unit allocated to the drive assembly. The simplest embodied structure of such assembly unit is for example composed of two aluminum U-profiles, each of which are firmly attached to the damper-carrier-surface at the front face. The assembly of the data storage device is accomplished in the so far described manner between the two bottoms of the U-profiles. The shanks of the U-profiles each form a nearly complete hollow shaft above and below the data storage device in lateral direction. Considering air-flow and noise, the remaining gap between the sides of the U-profiles are to be neglected.
If the type of housing mentioned previously comprises one or more data storage device(s), as described herein above, which are allocated to one or more assembly units, it is recommended that the assembly unit forms a hollow shaft around the data storage device, that the space between the upper and lower side of the data storage device to the corresponding inner sides of the hollow shafts are dimensioned in such a manner that xcex/4 of the highest acoustic frequency is not exceeded and that the construction forming the hollow shaft around the data storage device indicates low resonance properties so as to avoid acoustic stimulation of the hollow shaft.
Thereby, an unfolding of the noise pressure in full power within the hollow shaft is suppressed. Particularly all those sound waves are concerned, which unfold perpendicular from the data storage device surfaces. The upper-spectrum-waves are remnant as a remainder of the disturbing acoustic magnitude, which will then still be perceived as a gentle rustle. In the field of electric acoustics, the upper spectrum remnant due to filtering with high-pass filters is also known as pink noise. The xcex/4 dimensioning of the hollow shaft thereof is a mechanical high-pass filter in accordance to the invention. This mechanical xcex/4 high-pass filter thereby induces a strong attenuation of the stimulated air media, stimulated by the data storage device, in the immediate ambience of the data storage device surfaces. The effect of this measure is so powerful that sandwich foam linings are now dispensable. Thereupon, air-vent channels as described further on, may now be guided from the noise source through a partially reflecting cut-off surface at the end of the hollow shaft directly to the outside, without impairing the so far achieved low-noise emission. In consequence the xcex/4 dimensioning simultaneously enables a convenient maintenance of an optimum guided cooling air-stream above and below the data storage device, directly from the ambience to the interior. The cut-off surface my be formed by the damper-carrier-surface.
The air inlet of the housing is now accomplished by a plurality of aligned holes through the damper layers and the surface means in such a manner that the data storage device and assembly unit directly receive fresh cooling air from the outside of the housing. Thereby, one group of holes emerge on the outside of the U-profile hollow shaft and the others inside the hollow shaft. The advantage is, that an air stream is now simultaneously maintained across all surfaces of the data storage device and the cooling assembly- unit. Already with this embodiment a powerful cooling force is achieved with the least investment of material, as for example aluminum, and a far lower velocity of air circulation.
Thereupon, in accordance to the invention, no fan is any longer necessary for the cooling of even the most powerful disc drives. Of course, the cooling-force may be further elevated by adding cooling fins to the U-profiles. Further on, the advantage of this embodiment is that the required volume space in the housing and the weight of the assembly unit is strongly reduced. Due to the omission of a fan for the purpose of cooling the disc drive, the development of noise is further reduced. In the best instance, only one main fan remains in the power supply which maintains an air flow within the housing.
It is in particular of advantage, due to an improvement of the support-force distribution of the disc unit onto the dampers, if the application of an even softer damper material is made possible. The attenuation factor in relation to the chassis may be further elevated with a softer damper material. This is of advantage for a higher attenuation of the irregular head oscillations.
In a further embodiment of the invention, the data storage device is now supported completely free between two dampers. It is now of advantage, that fastening means no longer have to penetrate the supporting-surface. In this instance two suited supporting-surfaces which are arranged on two opposite facing sides of the drive assembly are necessary. The carrier-surface and fastening-surface-oscillation-dampers are now cast parts which in addition encompass each of the damper-carrier and fastening-surface on all sides. The supporting-surfaces which are arranged facing opposite to each other, comprise sleeves that are either integrated or additionally arranged, which again encompass each of the carrier-surface and the fastening-surface-oscillation-dampers on all sides. If the damper-carrier-surface is a distinct component and located at the front side of the data storage device, a suitable opening for the bus and power connector has to be aligned in each of the corresponding supporting-surface, the damper-fastening-surface and the fastening-surface-oscillation-damper. In order to achieve the counter-coupling conditions, the supporting-surfaces arranged facing opposite to each other, are required to maintain a mechanical stiff relation with each other. In the simplest instance this condition is achieved with a suitable cuboid shaped housing. Any other construction, such as an open one, may also fulfill this purpose. Two sides of the cuboid housing each of which are positioned opposite to each other, form the suitable supporting-surfaces for the carrier-surface-oscillation-damper and the fastening-surface-oscillation-damper. The remaining four sides of the cuboid then form the sleeves for the dampers. As the data storage device is now supported freely between the dampers, this arrangement also allows oscillations horizontally to the damper plane. In order to achieve counter-coupling for the horizontal oscillations as well, it is required to arrange the damper-extensions encompassing the data storage device, asymmetrically in their width. Thereupon, this embodiment is identical with the so far discussed, in terms of possible unfolding of their effects. As the weight load is now supported on two opposite facing sides of the drive assembly, it is a given possibility to apply even a softer damper material or to reduce the contact surfaces of the dampers. This leads to a further elevation of the damping factor against the housing. As previously explained, the aligned holes through the layers opposing each other, take care of the appropriate venting. It is of further advantage, that the cuboid shaped housing now forms another hollow shaft in such a manner, that the outer air stream is also guided to the outlet of the corresponding supporting-surface of the fastening-surface-oscillation-damper without mixing with the warmed up air. An advantageous side effect of the cuboid shaped housing is, that the inventive embodiments and the data storage device are now able to form a closed and therewith ESD protected unit.
Finally the herein above described embodiments lead to the conclusion that at least parts of the invention may be integrated parts of the data-storage-device-housing itself.